iOS实现文字转化成彩色文字图片

本文写了个将文字转化为多彩图片的功能，输入文字将文字转化为彩色的文字图片，可选择不同的字体，渐变，先看看效果。

实现主要用cagradientlayer渐变，先看看上部展示实现代码：

-(void)setupcontentview
{
 uiview *contentview = [[uiview alloc] initwithframe:cgrectmake(0, 44, screenwidth, screenhight - 44 -300)];
 [self.view addsubview:contentview];
 uitapgesturerecognizer *tapgesture = [[uitapgesturerecognizer alloc] initwithtarget:self action:@selector(tapgestureaction:)];
 [contentview addgesturerecognizer:tapgesture];
 self.topcontentview = contentview;
 self.topcontentview.backgroundcolor = [uicolor clearcolor];

 uilabel *label = [[uilabel alloc] init];
 label.numberoflines = 0;
 label.text = @"abc";
 label.frame = [self calculatecontextlabelframewithtitle:@"abc"];
 label.center = cgpointmake(contentview.bounds.size.width / 2, contentview.bounds.size.height / 2);
 label.font = [uifont fontwithname:self.fontnamearray[0] size:25];
 label.textalignment = nstextalignmentcenter;
 [contentview addsubview:label];
 label.backgroundcolor = [uicolor clearcolor];
 self.contentlabel = label;

 self.gradientlayer = [cagradientlayer layer];
 self.gradientlayer.frame = cgrectmake(label.frame.origin.x, label.frame.origin.y, label.frame.size.width, label.frame.size.height);
 self.gradientlayer.backgroundcolor = [uicolor clearcolor].cgcolor;
 self.gradientlayer.startpoint = cgpointmake(0,0.5);
 self.gradientlayer.endpoint = cgpointmake(1,0.5);
 self.gradientlayer.colors = self.grandentarr[0];
 [contentview.layer addsublayer:self.gradientlayer];
 self.gradientlayer.mask = self.contentlabel.layer;
 self.contentlabel.frame = self.gradientlayer.bounds;
}

当输入的文字改变时，重新计算 self.gradientlayer的frame

-(void)textfieldtextchange:(nsnotification*)notice
{
 self.contentlabel.text = self.textfield.text;
 [self recalculategradientlayerframe];
}

下部分的实现代码：

-(void)setupbottomview
{
 uiview *bottomview =[[uiview alloc] initwithframe:cgrectmake(0, screenhight - 300, screenwidth, 300)];
 bottomview.backgroundcolor = jgcolor(222, 222, 222);
 [self.view addsubview:bottomview];
 self.bottomcontentview = bottomview;

 uiview *textcontentview = [[uiview alloc] init];
 textcontentview.frame = cgrectmake(0, 0, bottomview.bounds.size.width, 50);
 [bottomview addsubview:textcontentview];
 textcontentview.backgroundcolor = jgcolor(55, 44, 16);

 uitextfield *textfield = [[uitextfield alloc] init];
 textfield.borderstyle = uitextborderstyleroundedrect;
 textfield.frame = cgrectmake(10, 5, textcontentview.bounds.size.width - 20, textcontentview.bounds.size.height - 10);
 [textcontentview addsubview:textfield];
 self.textfield = textfield;

 cgfloat orgy = 60;
 cgfloat orgx = 10;
 cgfloat space = 10;
 cgfloat width = (screenwidth - orgx * 2 - 3 * space) / 4;
 cgfloat height = 35;

 for (int i = 0; i < 16; i++) {
  uiview *vw = [[uiview alloc] initwithframe:cgrectmake(orgx + (i % 4) * width + (i % 4) * space, orgy + (i / 4) * height + (i / 4) * space, width, height)];
  vw.backgroundcolor = [uicolor clearcolor];
  vw.tag = i + 1;
  [self.bottomcontentview addsubview:vw];

  uitapgesturerecognizer *tapgesture = [[uitapgesturerecognizer alloc] initwithtarget:self action:@selector(viewtap:)];
  [vw addgesturerecognizer:tapgesture];

  uilabel *label = [[uilabel alloc] initwithframe:vw.bounds
       ];
  label.textalignment = nstextalignmentcenter;
  label.text = @"abc";
  label.frame = vw.bounds;
  label.font = [uifont fontwithname:self.fontnamearray[i % 4] size:25];
  label.backgroundcolor = [uicolor clearcolor];
  [vw addsubview:label];

  cagradientlayer *grandient = [cagradientlayer layer];
  grandient.frame = cgrectmake(label.frame.origin.x, label.frame.origin.y, label.frame.size.width, label.frame.size.height);
  grandient.backgroundcolor = [uicolor clearcolor].cgcolor;
  grandient.startpoint = cgpointmake(0,0.5);
  grandient.endpoint = cgpointmake(1,0.5);
  grandient.colors = self.grandentarr[i / 4];
  [vw.layer addsublayer:grandient];
  grandient.mask = label.layer;
  label.frame = grandient.bounds;
 }
}

将文字转化为图片的代码：

-(void)gettitleimg
{
 uigraphicsbeginimagecontext(self.topcontentview.frame.size);
 cgcontextref context = uigraphicsgetcurrentcontext();

 if ([[uidevice currentdevice].systemversion floatvalue] >= 7.0) {
  [self.topcontentview drawviewhierarchyinrect:self.topcontentview.frame afterscreenupdates:yes];
 }
 else
 {
  [self.topcontentview.layer renderincontext:context];
 }

 uiimage *img = uigraphicsgetimagefromcurrentimagecontext();
 uigraphicsendimagecontext();

 cgimageref newimgref = cgimagecreatewithimageinrect(img.cgimage, cgrectmake(self.gradientlayer.frame.origin.x, self.gradientlayer.frame.origin.y + 44, self.gradientlayer.frame.size.width, self.gradientlayer.frame.size.height));

 uigraphicsbeginimagecontextwithoptions(self.gradientlayer.frame.size, no, [uiscreen mainscreen].scale);
 context = uigraphicsgetcurrentcontext();

 cgcontexttranslatectm(context, 0, self.gradientlayer.frame.size.height);
 cgcontextscalectm(context, 1, -1);

 cgcontextdrawimage(context, cgrectmake(0, 0, self.gradientlayer.frame.size.width, self.gradientlayer.frame.size.height), newimgref);
 uiimage *newimg = uigraphicsgetimagefromcurrentimagecontext();
 uigraphicsendimagecontext();

 alassetslibrary *library = [[alassetslibrary alloc] init];
 [library toolwriteimagetosavedphotosalbum:newimg.cgimage metadata:nil completionblock:^(nsurl *asseturl, nserror *error) {

  if (error) {
   jglog(@"写入出错");
  }
 } groupname:@"相册名称"];

}

核心代码如上，主要运用到了cagradientlayer,截图，裁图的方法。
以上就是本文的全部内容，希望对大家的学习有所帮助。